PHP While循环不检索SQL中使用JOIN LEFT的多个行


PHP While loop not not retrieving more than one row in SQL that uses JOIN LEFT

我正在制作一个PHP SQL数据库来编录短篇小说。在显示故事的小摘录的索引页上,我试图使用while循环函数将表(故事)中的sql行显示为无序列表。故事的评级保存在另一个表中,我使用LEFT JOIN和唯一的列行"id"answers"storyid"将其链接到"stories"表。

加载时,数据显示正常,但是只显示了一行SQL,并且我的限制设置为50。while循环脚本和sql(close)脚本位于列表项的旁边。没有错误消息报告。

谁能建议为什么只有一个项目显示?

    <?php
            include("db.php");
            $query="SELECT s.*, AVG(r.rank) AS avrank
            FROM (SELECT *
                  FROM stories
                  WHERE id BETWEEN 1 AND 100
                  ORDER BY RAND()
                  LIMIT 50) AS s
            LEFT JOIN ratings AS r ON r.storyidr = s.id";
            $result=mysqli_query($connection,$query);
            ?>
    <ul id="tiles">
      <?php     
            while ($data = mysqli_fetch_assoc($result)):
            $id = $data['id'];
            $author = $data['author'];
            $page_path = $data['page_path'];
            $title = $data['title'];
            $avgrate = $data['avrank'];
            if(is_null($page_path)){$page_path = "#";}
            ?>
      <li>
        <div class="post-info">
          <h3><a href="create_page.php?id=<?php echo $id; ?>"><?php echo $title; ?></a></h3>
          <h3>rating is <?php echo $avgrate; ?>/5</h3>
          <span><a href="categories/<?php echo $category; ?>.php">
          <label> </label>
          </span> </div>
        <div class="post-info-rate-share">
          <form method="POST" action="rating.php?id=<?php echo $id; ?>">
            <fieldset class="rating">
              <legend> Rating: <?php echo $avgrate=round($avgrate,2); ?>/5</legend>
              <input type="radio" id="star5" name="starno" value="5" onclick="this.form.submit()"/>
            </fieldset>
          </form>
        </div>
      </li>
      <?php
            endwhile;
            mysqli_close($connection);
            ?>
    </ul>

您错过了GROUP BY:

SELECT s.*, AVG(r.rank) AS avrank
FROM stories s                  
LEFT JOIN ratings AS r ON r.storyidr = s.id
WHERE id BETWEEN 1 AND 100
GROUP BY s.id
ORDER BY RAND()
LIMIT 50;

演示:http://sqlfiddle.com/# !2/7a9fa/9